Our research focuses on three interrelated problems: (1) gene mapping of developmentally relevant genes, (2) transcriptional regulation of the transferrin receptor (TR) gene, and (3) the developmental role of the A- type homeobox genes in man and the laboratory mouse. Gene mapping will be used to determine if the linkage relationships of epigenetically relevant genes are conserved evolutionarily, and whether these linkage patterns are functionally significant. TR will be treated as a model system to study mechanisms which control cell division, and genes such as TR that are activated in dividing cells. The homeobox genes encode transcription factors which control the expression of genes relevant to the developmental process. Studies will be carried out to determine how these genes regulate themselves, how they respond to "input" genes, and how they control the coordinated patterns of expression of "target" genes. We see these three projects as interrelated, and we believe all three will contribute to a better understanding of the developmental process in mammals.